1. Field of the Art
Generally, for various purposes, many industrial machines are routinely required to make stepwise rotations of arbitrary stepping angles or to make arbitrary stepwise rotations in both forward and reverse directions.
This invention relates to a rotary stepping actuator which can meet such requirements by converting rectilinear reciprocating movements into stepwise or stepping rotations of an arbitrary number of steps, and more particularly to a rotary stepping actuator which is capable of converting rectilinear reciprocating movements into stepwise or stepping rotation advancing through a predetermined angle in each step, in such a way as to permit its application to those cases in need of stepwise rotations of an arbitrary number of steps in one direction or in both forward and reverse directions.
2. Description of the Prior Art
It has been the general practice in the art to resort to a servo motor in those cases where stepwise rotations of certain stepping angles are required or where stepwise rotations in both forward and reverse directions are required. However, the servo motors invariably necessitate to provide a control system which is complicate and very expensive, and even the mechanical type which is capable of rotations arbitrarily in both forward and reverse directions is relatively complicate in construction and control, let alone the problem that it is difficult to obtain large torques.
As a simpler means for obtaining stepwise rotations of a given stepping angle, there has thus far been known in the art a mechanism employing a rectilinearly reciprocating member and a rotating member which are coupled with each other in such a manner that an axial straight movement of the reciprocating member is converted into a certain angular rotation of the rotating member, by means of a helical groove provided on one of the two coupled members and a tracking projection provided on the other one of the coupled members in engagement with the helical groove thereby to convert axial reciprocating movements of the rectilinear drive member into alternate rotational movements of the rotating member which is in a restrained state in the axial direction.
Despite the advantage of simplicity in construction, what one can obtain from the mechanism of this sort as the output of the rotating member is simply rocking movements within a certain angular range, and it is difficult to obtain stepwise rotations consisting of a given number of steps in one direction or in both forward and reverse directions or to obtain infinite stepping rotations in a given direction.